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Subject: Agronomy × Author: Dhillon, Buta Singh × End date: 2019 × Start date: 2010 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Nutritional and physiological studies on sunflower (Helianthus annuus L.) under staggered planting
    (Punjab Agricultural University, Ludhiana, 2016) Dhillon, Buta Singh; Sharma, P.K.
    Investigations entitled “Nutritional and physiological studies on sunflower (Helianthus annuus L.) under staggered planting” were undertaken at Research Farm of Department of Agronomy, Punjab Agricultural University, Ludhiana during spring 2014 and 2015. The soil of experimental fields was loamy sand in texture, medium in available N during 2014 in case of experiment-I and low in available N in case of experiment –II. However, soil was low in available N in both the experiment during 2015. Experimental fields were high in available P, medium in K and sufficient in B during both the years. The experiments were laid out in split plot design keeping combinations of three sowing dates (January 20, February 10 and March 2) and two intra row spacings (30 and 24 cm) in main plots and four N doses (0, 45, 60 and 75 kg ha-1) in sub-plots in case of experiment-I. The experiment-II consisted of three sowing dates (January 20, February 10 and March 2) in main plots and eight foliar application treatments (control, water spray, boron @ 110, 220, 440 ppm, TIBA @ 100, 200, 400 ppm) in sub-plots. Number of days taken for initiation and completion of emergence as well as emergence percentage were found to decrease with delay in sowing. Growth and photosynthetic parameters of later sown crop were higher than earlier sown crop during initial life span of crop, which were reversed in the later part of life span except plant height. Crop sown on January 20 recorded higher pre-and post-anthesis dry matter accumulation, N accumulation and N translocation to seed. Due to its better growth, interception of PAR was higher with lower canopy temperature. It availed longest vegetative and reproductive phases, consequently resulted in better yield contributing characters and higher seed yield. Crop sown on March 2 experienced higher temperature at all pheno-phases leading to reduction in growth and seed set. Nitrogen use efficiency, pollen viability, pollen load and vascularisation were also reduced under delayed sowing, resulting into lower seed yield. Oil content and oil yield decreased but protein content increased due to delay in sowing. Decrease in linoleic acid coupled with increase in oleic acid were also observed due to delay in sowing. The effect of intra row spacings on seed yield was not conspicuous as significantly better yield contributing characters of wider sown crop compensated the benefit of higher plant population under closer sowing. However, closer sown crop produced significantly higher biological yield but had lower harvest index than wider sown crop. Seed yield of closer sown crop was 1.9 % higher than wider sown under D1 and it rose to 9.9 % under D3. Oil content, oil yield, protein content and fatty acid composition were not influenced by intra row spacing. Application of N resulted in better growth and photosynthetic parameters, which was reflected in higher dry matter accumulation, dry matter translocation, N accumulation and N translocation to seed leading to significant improvement in seed yield up to 60 kg ha-1 in medium and up to 75 Kg ha-1 in poor fertility soil. The interactive effects of sowing date with N doses indicated that magnitude of increase in seed yield due to N application was higher under D1 than under later sowing. Application of N reduced the oil content with concomitant increase in protein content and oil yield. However, fatty acid composition was not affected by N doses. Foliar application of boron and TIBA improved growth, photosynthetic parameters, pollen viability (due to boron only), vascularisation, dry matter accumulation and its translocation, consequently higher seed yield over control under all sowing dates. The reduction in seed yield due to delayed sowing was overcome by foliar application of all the chemicals except TIBA 400 ppm on March 2 sown crop. Averaged over sowing dates and years, application of boron @ 110, 220, 440 ppm and TIBA @ 100, 200, 400 ppm increased the seed yield by 11.2, 15.5, 16.1% and 18.8, 21.5, 13.8 %, respectively. Oil content and fatty acid composition did not differ but improvement in oil yield and protein content was observed in response to foliar application of boron and TIBA.